The present invention relates generally to fuel pumps for vehicles and, more particularly, to a pump section for a fuel pump of a vehicle.
It is known to provide a fuel tank in a vehicle to hold fuel to be used by an engine of the vehicle. It is also known to provide a fuel pump to pump fuel from the fuel tank to the engine. One type of fuel pump is known as a high-pressure turbine fuel pump. The high-pressure turbine fuel pump typically includes a pump section having an impeller rotatable between inlet and outlet plates. The impeller is of a closed vane type to improve pump efficiency and performance. The impeller has a hub portion, a plurality of blade tips extending radially from the hub portion and disposed circumferentially thereabout, power, or stumbling are shortfalls. Reduction in the loss of flow can be achieved by understanding vapor formation regions within the pump section and finding ways to address them.
Previous designs for the pump section positioned the inlet and outlet ports to match the flow channel to produce a fluid volume into both upper and lower channels of the flow channel via the impeller at the same time and position. Open vane impellers use this technique in order to start a regenerative cycle as soon as possible. Closed vane V-shaped blade impellers, however, use a tangential action of the fluid particles in order to drive the fluid at lower speeds, thereby producing a higher back pressure on the blade and causing the passage to fill both upper and lower channels to occur at differing positions and times within the in-take area for the pump section. The vapor generated by V-shaped blades in the intake area of the pump section approaches 5 psig (35 kPa) suction and, if not replaced with fuel, a vacuum can cause the vapor to be carried into the flow channel before being expelled through the outlet port.
Therefore, it is desirable to provide a pump section for a fuel pump that reduces or eliminates fuel vapors therein. It is also desirable to provide a pump section for a fuel pump to handle hot fuel therein. It is and a peripheral ring portion extending radially from the blade tips.
The ability of the pump section to produce a desired flow and pressure at environments present in fuel tanks is based on expelling the fuel vapors as efficiently as possible. The passage of V-shaped blades through the flow path channel produces a negative pressure on a backside of the blade itself. This xe2x80x9cvacuumxe2x80x9d displaces fuel particles that produce a fluid volume needed to achieve flow targets at given speed and pressures. At colder fuel tank temperatures, the volatility of the fuel is very stable and negative pressures seen in an inlet area of the pump section do not affect a vapor-liquid ratio. When higher temperatures occur (40 to 50 degrees Celsius), particles of air and fuel mix together with the resultant rich vapor content of the fuel and reduce the ability of the impeller to displace the volumetric fluid.
The loss of flow in the fuel pump due to elevated fuel temperatures in the fuel tank is the result of the inability of the pump section to purge vapors efficiently. The volatility of gasoline and/or reformulated gasoline at elevated temperatures is the main source for flow loss. The pump section also has lower efficiencies purging the vapors at high flow rates. For applications where the higher flow rates are demanded by an engine management system, drivability issues, loss of further desirable to provide a pump section for a fuel pump, which maximizes performance.
It is, therefore, one object of the present invention to provide a new pump section for a fuel pump in a fuel tank of a vehicle.
It is another object of the present invention to provide a pump section for a fuel pump of a vehicle that reduces or eliminates vapors generated by hot fuel.
To achieve the foregoing objects, the present invention is a fuel pump for a vehicle including a pump section having a flow channel and a rotatable impeller cooperating with the flow channel to pump fuel therethrough. The fuel pump also includes a motor section disposed adjacent the pump section and having a motor to rotate the impeller. The fuel pump further includes an outlet section disposed adjacent the motor section to allow pumped fuel to exit the fuel pump. The impeller has a plurality of blades that are generally V-shaped. The pump section has an inlet port and an outlet port communicating with the flow channel and having a shape according to a face angle of the blades.
One advantage of the present invention is that a new pump section is provided for a fuel pump in a fuel tank of a vehicle. Another advantage of the present invention is that the pump section has a channel for both the inlet plate and the outlet plate for eliminating vapors inherent or produced by passing V-shaped blades on an impeller at the in-take area of the pump section. Yet another advantage of the present invention is that the pump section handles hot fuel and maximizes performance greater than conventional pump sections for high flow/high output applications due to the geometry of rejecting the entrance of fuel vapor generated in an inlet channel of the outlet plate. Still another advantage of the present invention is that the pump section has an outlet port design for increasing flow channel arc length, thereby increasing performance for low delta pressures as the fluid exits the high-pressure pump section. A further advantage of the present invention is that the pump section has xe2x80x9cport timingxe2x80x9d dictated by fluid particles through the V-blade impeller at both the inlet and outlet areas. Yet a further advantage of the present invention is that the pump section eliminates fuel vapor generation by eliminating dead areas in the ports. Still a further advantage of the present invention is that the pump section allows the fuel pump to handle hot fuel at high flow rates (40 g/s at 350 kPa).